Improvement in hot-air engines



naar ,time

THOMAS MCDONGUGH, 0F NEWBURG, NEW YORK.

Letters Patent No. 96,335, aan@ November 2,1869.

The Schedule refen'e to in these Letters ,Patent and making part of the same.

Be it known that I, THOMAS McDoNoUGH, of Newburg, in the county of Orange, and State of New York, have invented a new and useful Improvemeut on the Air-Engine; and I do hereby declare that the following is a full, clear, and exact description of the construction and operation of the same, reference being had to the annexed drawings, making a part of this specification, iu which- Figure l is a' longitudinal elevation in section;

Figure 2 is a transverse section at the part marked ain iig.1;and

Figure 3, also a transverse section at b in fig. 1.

I make a cylinder, el, either of sheet or cast-iron, closed air-tight at the bottom, and open at the top.

Within this I put-a thin sheet-iron cylinder, c2, open at both ends, and shorter than the external cylinder c1. l This is cut with openings around its lower edge, so as'to touch the bottom of cl in but few places.

The space between the two cylinders is filled with wire gauZeV G.

Within the inner cylinder c2, I place a plunger, pl, which has hemp packing H H wrapped around it, near its upper end, so thatit may slide nearly air.- tightiu c2.

A piston, P, with ordinary packing,l slides in the upper or open end of c1, with` a hollow piston-rod running through a guide above it.

Th'c plunger-rod runs through this piston-rod, and each of the rods is connected to one of tWo cranks on a shaft, S, placed across c1, as near the centre as the piston-rod will allow.

A ily-wheel is fastened on this shaft.

Small metal balls m b are dropped into the inner cylinder, so as to lie on the bottom of the outer cylinder.

The machine is then stpod upon a small furnace or over a gas-jet, till the bottom is heated.

The contained air that is below the piston, having no communication Awitlrjthe external air, on moving thewheel in the direction indicated by the arrow near the Shaft in fig, l, the .plungeniu rising, movesthe lair that is between its top and the piston, Vdown through the wire gauzev and the balls.,

By its heating and expansion, this air moves up the l pistou.

By continuing to turn the wheel,l and moving the plunger down, the air is forced back through the wire and the machine completes one revolution, after which it will continue to act', increasing its-speed to two hundred revolutions per minute, and furnishes pow'ersuficient to drive sewing-machines or other light work.`

The machine may be stopped either by pressure against the wheel, or by opening a cock at any part below the pistou, so as to communicate with the ex'- ternal air.

I claim, and desire to secure by Letters Patent- 1. The arrangement of the shaft directly over the cylinder, substantially as described.

2. The combination of the two cylinders with'thc balls and shaft, to form an air-engine, substantially as described.

THOMAS MCDONOUGH.

Viitnesses;

DARWIN W. EsMoNDL JN0. C. Non. 

